Question 1

Which of the following best describes the First Law of Thermodynamics as it applies to biological systems?

Accepted Answer

Energy can be transferred and transformed, but it cannot be created or destroyed.

Question 2

A reaction has a negative $\Delta G$. What does this indicate about the reaction?

Accepted Answer

The reaction is spontaneous and releases free energy.

Question 3

Which of the following is true about enzymes?

Accepted Answer

Enzymes lower the activation energy, increasing the rate of reaction.

Question 4

Which equation correctly relates free energy change to enthalpy and entropy?

Accepted Answer

$\Delta G = \Delta H - T\Delta S$

Question 5

A fish has a metabolic rate of 120 J/hr at 10°C and 240 J/hr at 20°C. What is the Q10 value for this metabolic process?

Accepted Answer

$Q_{10} = \frac{240}{120} = 2$

Question 6

Which of the following statements about ATP is correct?

Accepted Answer

ATP hydrolysis releases energy by breaking a phosphoanhydride bond.

Question 7

Which of the following best describes non-competitive inhibition?

Accepted Answer

The inhibitor binds to a site other than the active site, changing enzyme conformation.

Question 8

Which of the following is a correct statement about the Michaelis-Menten constant ($K_m$)?

Accepted Answer

$K_m$ is the substrate concentration at which the reaction rate is half-maximal.

Question 9

Which of the following is an example of feedback inhibition in metabolic pathways?

Accepted Answer

A product of a pathway inhibits an enzyme that acts early in the pathway.

Question 10

Which of the following best describes cooperativity in enzymes?

Accepted Answer

Binding of one substrate molecule increases the enzyme's affinity for additional substrate molecules.

Question 11

Which of the following is NOT a function of enzymes?

Accepted Answer

Changing the equilibrium position of a reaction.

Question 12

Which of the following is true about competitive inhibition?

Accepted Answer

The inhibitor binds to the active site, competing with the substrate.

Question 13

Which of the following best describes the role of kinases in metabolism?

Accepted Answer

Kinases add phosphate groups to molecules using ATP.

Question 14

A reaction has $\Delta H = -50$ kJ/mol and $\Delta S = -0.1$ kJ/(mol\cdot K). At $T = 300$ K, what is $\Delta G$?

Accepted Answer

$\Delta G = -50 - (300 	imes -0.1) = -20$ kJ/mol

Question 15

Which of the following is a correct statement about allosteric regulation?

Accepted Answer

Allosteric regulators bind to a site other than the active site, changing enzyme activity.

Question 16

Which of the following is true about the effect of temperature on enzyme activity?

Accepted Answer

Enzyme activity increases with temperature up to an optimum, then decreases due to denaturation.

Question 17

Which of the following best describes the induced fit model of enzyme function?

Accepted Answer

The enzyme changes shape to fit the substrate upon binding.

Question 18

Which of the following is a correct statement about isoenzymes?

Accepted Answer

Isoenzymes are different enzymes that catalyze the same reaction.

Question 19

Which of the following is true about the effect of pH on enzyme activity?

Accepted Answer

Each enzyme has a specific optimal pH at which it functions best.

Biochemistry Study Guide: Thermodynamics, Metabolism, and Enzyme Function

Study Guide - Practice Questions